JP2655098B2 - Wafer surface treatment equipment using chemicals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer surface processing apparatus for performing processes such as forming an electroless plating film on a wafer surface using a chemical solution and forming an oxide insulating film.

[0002]

2. Description of the Related Art Conventionally, as a wafer surface treatment apparatus of this kind, an apparatus having a structure as shown in FIG. 2 is known. FIG.
As shown in FIG.
Is filled and the wafer 10 immersed in the chemical solution 103
4. An overflow type processing tank 101 for performing a surface treatment.
And an outer tank 102 for receiving a chemical solution 103 overflowing from the processing tank 101.
Are connected to each other by a pipe 107 provided with a pump 105 and a filtration unit 106 at an intermediate portion. Pump 1
05 is constantly driven during processing of the wafer 104,
The chemical solution 103 received in step 02 is returned to the processing tank 101 to circulate the chemical solution 103. The filtration unit 106 is disposed between the processing tank 101 and the pump 105 and filters foreign substances and the like in the chemical solution 103.

[0003] Further, when the surface of the wafer 104 is treated, it is necessary to maintain the temperature of the chemical solution 103 in the processing bath 101 at a constant temperature. A mechanism 110 is provided. The temperature control mechanism 110 controls the chemical 1 in the processing tank 101.
A temperature sensor 111 for detecting the temperature of the processing tank 10;
It comprises a temperature controller 113 for adjusting the temperature of the chemical solution 103 in the processing tank 101 by heating / cooling 1 and a controller 112 for controlling the temperature controller 113 in accordance with the detection result of the temperature sensor 111. . By adjusting the temperature of the chemical solution 103 with the temperature adjusting mechanism 110, for example, the growth rate of an electroless plating film, an oxide insulating film, or the like is kept constant.

[0004] In the above-described conventional example, in order to keep the temperature of the chemical solution 103 in the processing tank 101 at a constant temperature, the processing tank 101 is maintained.
Although the example in which the temperature of the temperature is directly controlled is shown,
In place of 0, a device in which a chemical solution temperature control unit (not shown) is provided between the filtration unit 106 and the processing tank 101 has been proposed. In this example, after the temperature of the chemical solution 103 is adjusted to the constant temperature in the chemical temperature control section, the temperature is supplied to the processing tank 101 and the processing tank 101
The temperature of the chemical solution 103 is kept constant (Japanese Patent Application Laid-Open
No. 16427).

[0005]

In the above-described conventional wafer surface treatment apparatus, the temperature of the chemical is adjusted to be a temperature required for performing the surface treatment on the wafer. There is not much change in temperature. Therefore, when such a wafer surface treatment apparatus is used, for example, for forming an electroless plating film or a liquid phase oxide film, the foreign matter captured by the filtration unit becomes a nucleus and the plating film or the oxide film is formed in the filtration unit. However, there is a problem that the clogging of the filtration part easily progresses.

Accordingly, an object of the present invention is to provide a wafer surface treatment apparatus capable of preventing clogging of a filtration section and efficiently performing surface treatment on a wafer.

[0007]

In order to achieve the above object, a wafer surface treatment apparatus according to the present invention is an overflow type treatment for holding a chemical solution and performing surface treatment on the wafer by immersing the wafer in the chemical solution. A tank, a temperature control mechanism for maintaining the temperature of the chemical in the processing tank at a predetermined temperature, a pipe for circulating the chemical overflowing from the processing tank to the processing tank, and a foreign substance in the chemical passing through the pipe. A filtration unit for filtering the liquid, wherein a second temperature control mechanism for controlling the temperature of the chemical solution in the filtration unit to a temperature at which a precipitate is not generated from the chemical solution is provided. And

Further, the surface treatment may be a film forming treatment for forming a film containing a part of the components in the chemical solution on the surface of the wafer. In this case, the film forming process includes an electroless metal film forming process and a liquid phase oxide film forming process.

[0009] Further, the temperature of the chemical solution flowing through the portion of the pipe between the filtration section and the processing tank is determined by the temperature of the chemical solution in the filtering section and the temperature of the chemical solution in the processing tank. May have a third temperature adjustment mechanism for adjusting the temperature to a temperature in the range between.

[0010]

In the wafer surface treatment apparatus of the present invention configured as described above, the wafer is subjected to the surface treatment by immersing the wafer in the chemical solution filled in the processing tank. The processing tank is of the overflow type, and the chemical overflowing from the processing tank is
After the foreign matter is filtered by the filtration unit through the pipe, the foreign matter is returned to the processing tank again. Here, since the filtration unit is provided with the second temperature control mechanism for adjusting the temperature at which no precipitate is generated from the chemical solution in the filtration unit, no precipitate is generated in the filtration unit, and Clogging of the filtration unit is prevented. Further, since no precipitate is generated in the filtration unit, the concentration of the chemical solution does not fluctuate, and the surface treatment on the wafer is stably performed.

In general, when the surface treatment of a wafer is a film forming process for forming a film containing components in a chemical solution on the surface of the wafer, the chemical solution in the processing bath is maintained at a temperature necessary for deposition or formation of the film. As a result, the substance constituting the membrane is easily deposited or generated even in the filtration section. Therefore, adjusting the temperature of the filtration unit as described above is particularly effective in the case of a film forming process.

Further, in the case where a third temperature control mechanism is provided in a portion of the pipe between the filtration portion and the treatment tank, the temperature of the chemical solution flowing through the portion is determined by the temperature of the chemical solution in the filtration portion and the temperature of the treatment solution. The temperature is adjusted to between the temperature of the chemical in the bath. Therefore, when the chemical solution whose temperature has been adjusted by the filtration unit is supplied to the processing tank again, the temperature of the supplied chemical solution reaches the temperature of the processing tank without difficulty.

[0013]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic structural view of an embodiment of a wafer surface treating apparatus according to the present invention. As shown in FIG.
And an overflow-type processing tank 1 for performing a surface treatment on the wafer 4 immersed in the chemical solution 3, and an outer tank 2 for receiving the chemical solution 3 overflowed from the processing tank 1,
The point that the treatment tank 1 and the outer tank 2 are communicated with each other by a pipe 7 provided with a pump 5 and a filtration unit 6 in the middle part is as follows.
This is the same as a conventional wafer surface treatment apparatus.

What is different from the conventional wafer surface treatment apparatus is that
As a means for adjusting the temperature of the chemical solution 3, three temperature adjusting mechanisms for independently adjusting the temperature of the chemical solution 3 are provided. That is, a first temperature control mechanism 10 for controlling the temperature of the chemical solution 3 in the treatment tank 1, a second temperature control mechanism 20 for controlling the temperature of the chemical solution 3 in the filtration unit 6,
A third temperature control mechanism 30 that controls the temperature of the chemical solution 3 flowing through the pipe 7 between the filtration unit 6 and the processing tank 1.

The first temperature control mechanism 10 is, like the temperature control mechanism 110 shown in FIG. 2, a temperature sensor 11 for detecting the temperature of the chemical solution 3 in the processing tank 1, and heating and cooling the processing tank 1. The temperature controller 13 adjusts the temperature of the chemical solution 3 in the processing tank 1 by the above-described method, and the controller 12 controls the temperature controller 13 according to the detection result of the temperature sensor 11. The second temperature adjustment mechanism 20 includes a temperature sensor 21 that detects the temperature of the chemical solution 3 flowing through the pipe 7 between the pump 5 and the filtration unit 6, and a filter inside the filtration unit 6 by adjusting the temperature of the filtration unit 6. Temperature controller 2 for adjusting the temperature of the chemical solution 3
3 and the temperature controller 2 according to the detection result of the temperature sensor 21.
3 and a controller 22 for controlling the controller 3. The third temperature control mechanism 30 includes a temperature sensor 3 that detects the temperature of the chemical solution 3 flowing through the pipe 7 between the filtration unit 6 and the processing tank 1.
1, a temperature controller 33 for adjusting the temperature of the chemical solution 3 in the region by adjusting the temperature of the pipe 7 between the filtration unit 6 and the processing tank 1, and a temperature controller 33 for adjusting the temperature in accordance with the detection result of the temperature sensor 31. The controller 32 controls the controller 33.

Based on the above configuration, the chemical solution 3 in the processing tank 1
Is maintained at a constant temperature required for the surface treatment of the wafer 4 by the first temperature control mechanism 10, and the surface of the wafer 4 is subjected to processing by immersing the wafer 4 in the chemical solution 3.

The chemical 3 overflowing from the processing tank 1 is received by the outer tank 2 and returned to the processing tank 1 by the pump 5 through the pipe 7. On the way, foreign substances and the like in the chemical solution 3 are filtered by the filtration unit 6. In addition, the filtration unit 6 is controlled by the second temperature control mechanism 20 so that the temperature of the chemical solution 3 in the filtration unit 6 is set to a temperature at which no production reaction occurs or a dissolution reaction temperature. No precipitate is formed.

The temperature of the chemical solution 3 between the filtration unit 6 and the processing tank 1 is the difference between the temperature controlled by the first temperature control mechanism 10 and the temperature controlled by the second temperature control mechanism 20. It is adjusted so that the temperature is between. Thereby, the second
The chemical solution 3 whose temperature has been adjusted by the temperature adjusting mechanism 20 reaches a constant temperature required for the surface treatment of the wafer 4 without difficulty, so that the temperature change of the processing bath 1 can be small.

Next, a specific example of the surface treatment of the wafer 4 using the above-described wafer surface treatment apparatus will be described with reference to FIG.

(Embodiment 1) A case where a liquid phase oxide film is formed on a wafer 4 will be described. Generally, the liquid phase oxide film is formed by selectively forming an oxide insulating film on the surface of the wafer 4 using a reversible reaction of a silicofluoric acid solution (SiF ₆ ).
By controlling the temperature of the solution, it is possible to control the production reaction and the dissolution reaction.

For example, as the chemical solution 3, A
In addition to using the solution to which l is added, the temperature of the chemical solution 3 in the processing tank 1 is adjusted by the first temperature adjusting mechanism 10 so as to be 35 to 40 ° C., which is the temperature at which the oxide insulator is deposited. Then, the wafer 4 is immersed in the chemical solution 3 and the pump 5
By circulating and filtering the chemical solution 3 using the method, an oxide insulating film is selectively formed on the surface of the wafer 4.

At this time, the temperature of the chemical solution 3 in the filtration unit 6 is adjusted by the second temperature control mechanism 20 to 20 to 30 in the dissolution reaction direction.
The temperature is adjusted to 25 ° C., and the temperature of the chemical solution 3 flowing through the pipe 7 from the filtration unit 6 to the processing tank 1 is adjusted to 30 to 35 ° C. by the third temperature adjusting mechanism 30. As described above, since the chemical solution 3 is cooled to the dissolution reaction temperature in the filtration unit 6, the filtration unit 6 does not generate an oxide insulator with the captured foreign matter as a nucleus. No clogging occurs. Specifically, the clogging of the filtration unit 6 has occurred in about 5 hours after the start of the treatment in the past, but by controlling the temperature of the filtration unit 6 as in the present embodiment, the continuous treatment for 24 hours was performed. Became possible. Further, since no precipitate of the chemical solution 3 is generated in the filtering unit 6, the concentration of the chemical solution 3 does not fluctuate, and the film can be stably grown on the wafer 4.

On the other hand, since the chemical solution 3 cooled in the filtration section 6 is heated to a temperature close to the reaction temperature for the deposition of the oxide insulator before returning to the processing tank 1, the chemical solution 3 can be easily returned to the processing tank 1. The temperature of the processing tank 1 is reached. Thereby, the processing tank 1
Is small, and the film growth on the wafer 4 can be performed more stably.

(Embodiment 2) Next, a case where an electroless gold plating film is formed on the wafer 4 will be described. Generally, an electroless gold plating film is formed by controlling the temperature of a gold sulfite solution by a method of selectively forming a plating gold film on the surface of the wafer 4 by using a redox reaction of gold sulfite. It is possible to control the reaction rate.

For example, a solution containing gold sodium sulfite as a main component is used as the chemical solution 3, and the temperature of the chemical solution 3 in the processing tank 1 is controlled by the first temperature control mechanism 10 at a temperature at which a plating gold film is deposited. The temperature is adjusted to a certain value of 65 to 70 ° C. Then, the wafer 4 is immersed in the chemical solution 3 and the pump 5
By circulating and filtering the chemical solution 3 by using, a plated gold film is selectively formed on the surface of the wafer 4.

At this time, the temperature of the chemical solution 3 in the filtration unit 6 is controlled by the second temperature control mechanism 20 to 20 to 20 at which no generation reaction occurs.
The temperature is adjusted to 25 ° C., and the temperature of the chemical solution 3 flowing through the pipe 7 from the filtration unit 6 to the processing tank 1 is adjusted to 60 to 65 ° C. by the third temperature adjusting mechanism 30. As described above, since the filtering section 6 is cooled to a temperature at which the chemical solution 3 does not generate and react, the plating section 6 having the captured foreign matter as a nucleus is not abnormally generated. No clogging of No. 6 occurs. Further, since the abnormal generation of the plating gold does not occur in the filtration unit 6, the concentration of the chemical solution 3 does not change, and the plating gold film can be stably grown on the wafer 4.

On the other hand, the chemical solution 3 cooled in the filtration unit 6 is heated to a temperature close to the deposition temperature of the plated gold film before returning to the processing tank 1, so that the chemical solution 3 can be processed without difficulty even if returned to the processing tank 1. The temperature of the bath 1 is reached. Thereby, the temperature change of the processing bath 1 can be small, and the formation of the plated gold film on the wafer 4 can be performed more stably.

In the above-described embodiment, the filtering unit 6 and the processing tank 1
The example in which the third temperature control mechanism 30 is provided in the pipe 7 between the above and the above, but the temperature difference between the temperature set in the filtration unit 6 and the temperature set in the processing tank 1 is not large, In the case where the first temperature control mechanism 10 is provided in the pipe 7 between the filtration unit 6 and the processing tank 1 and the chemical solution 3 adjusted to a predetermined temperature is supplied to the processing tank 1 (for example, Japanese Unexamined Patent Publication No. Sho 6
No. 0-16427)
In this case, the third temperature control mechanism 30 can be omitted. Conversely, the temperature difference between the temperature set in the filtration unit 6 and the temperature set in the processing tank 1 is large, and the third temperature setting mechanism 3
If the temperature of the chemical solution 3 supplied to the processing tank 1 cannot be adjusted to near the temperature set in the processing tank 1 with only 0, in addition to the third temperature adjusting mechanism 30, at least one other temperature adjustment A mechanism may be provided in series with the pipe 7, and the temperature of the chemical solution 3 flowing through the pipe 7 may be gradually brought close to the temperature set in the processing tank 1.

[0030]

As described above, the wafer surface treatment apparatus according to the present invention is provided with the second temperature control mechanism for adjusting the temperature at which no precipitate is generated from the chemical solution in the filtration section. Is not generated, so that clogging of the filtration unit by the precipitate can be prevented. As a result, the surface treatment of the wafer can be continuously performed for a long time, and the surface treatment of the wafer can be efficiently performed. In addition, since no precipitate is generated, a change in the concentration of the chemical solution does not occur, and the surface treatment on the wafer can be stably performed.

This is particularly effective when the surface treatment of the wafer, such as the formation of an electroless metal film or the formation of a liquid phase oxide film, is a film formation treatment for forming a film containing components in a chemical solution on the surface of the wafer. It is.

Further, by providing a third temperature control mechanism in a portion of the pipe between the filtration section and the processing tank, when the chemical is supplied to the processing tank again, the temperature of the supplied chemical can be controlled without difficulty. The temperature of the processing tank can be reached. As a result, the change in the temperature of the processing bath can be small, and the surface treatment of the wafer can be performed more stably.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of one embodiment of a wafer surface treatment apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional wafer surface processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing tank 2 Outer tank 3 Chemical solution 4 Wafer 5 Pump 6 Filtration part 7 Piping 10 First temperature control mechanism 11, 21, 31 Temperature sensor 12, 22, 32 Controller 13, 23, 33 Temperature controller 20 Second temperature Adjustment mechanism 30 Third temperature adjustment mechanism

Claims (5)

(57) [Claims] 1. An overflow type processing tank for holding a chemical solution and performing a surface treatment on the wafer by immersing the wafer in the chemical solution, and a temperature control for maintaining a temperature of the chemical solution in the processing tank at a predetermined temperature. A mechanism, a pipe for circulating the chemical solution overflowing from the processing tank to the processing tank, and a filtering unit for filtering foreign substances in the chemical solution passing through the pipe, a wafer surface processing apparatus, A wafer surface treatment apparatus having a second temperature control mechanism for controlling the temperature of the chemical solution to a temperature at which no precipitate is generated from the chemical solution. 2. The wafer surface treatment apparatus according to claim 1, wherein the surface treatment is a film formation treatment for forming a film containing a part of components in the chemical solution on the surface of the wafer. 3. The wafer surface processing apparatus according to claim 2, wherein the film forming process is an electroless metal film forming process. 4. The wafer surface processing apparatus according to claim 2, wherein said film forming process is a liquid phase oxide film forming process. 5. A method for measuring the temperature of a chemical solution flowing through a portion of the pipe between the filtration unit and the processing tank, the temperature of the chemical solution in the filtering unit and the temperature of the chemical solution in the processing tank. The wafer surface treatment apparatus according to any one of claims 1 to 4, further comprising a third temperature adjustment mechanism for adjusting the temperature to a value between the temperature and the temperature.